The present invention relates generally to image retaining cards. More particularly, the present invention relates to image retaining cards for such things as identification cards, a driver""s licenses, passports, and the like.
Identification cards and related products have been used for many years as a means for persons to establish their identity and credentials. These identification cards are typically kept on the person of the card holder. For example, the card may be kept in the card holder""s wallet. Identification cards are often utilized on a daily basis to obtain entrance into a controlled area. During daily use, the identification card may be flexed repeatedly. Even when inside a wallet, the identification card may be subjected to repeated flexing. Identification cards frequently develop cracks, and/or delaminate due to repeated flexing during use.
An image retaining card in accordance with the present invention may be utilized as an identification card, a driver""s license, a passport, etc. An image retaining card in accordance with the present invention comprises a substrate structure, a cover, and an image receptive material disposed between the substrate structure and the cover. The substrate structure comprises a substrate layer and a preferred but optional substrate tie layer.
In a useful embodiment, the substrate layer of the substrate structure comprises a polyolefin. In a particularly useful embodiment, the substrate layer of the substrate structure comprises polypropylene. In a preferred method in accordance with the present invention, the substrate layer and the optional substrate tie layer are formed utilizing a co-extrusion process. In a particularly preferred embodiment, the substrate layer comprises a blend of materials including the tie layer material to enhance the adhesion between substrate tie layer and substrate layer.
An image retaining card including polypropylene exhibits good abrasion resistance, low cost, and good crack resistance. In a preferred embodiment, the substrate tie layer of the substrate structure comprises functionalized polyolefin. An image retaining card including a substrate tie layer comprising functionalized polyolefin exhibits good resistance to delamination.
In one embodiment, the image receptive material is comprised of a microporous polymeric film. An identification card comprising an image retaining card including a microporous polymeric film and an image printed on the microporous polymeric film exhibits desirable anti-tampering characteristics. In particular, if an image retaining card in accordance with the present invention is delaminated the printed image will be substantially distorted andlor destroyed. For example, during delamination, the image receptive material may stretch, distorting the image.
In a preferred embodiment, the image receptive material is adapted to receive an aqueous ink from an inkjet printer. Aqueous ink from an inkjet printer is preferred because inkjet printers are readily available at low cost.
In a preferred embodiment, the image retaining card includes a printed image having one or more security indicia. Examples of security indicia which may be suitable in some applications include, a picture of a human face, a representation of a human finger print, and a representation of a cardholder""s signature.
In a preferred embodiment, the cover comprises an optically transparent polymeric film. An optically transparent polymeric film is preferred, so that the printed image may be viewed through the cover. Also in a preferred embodiment, the cover is fixed to the image receptive material, for example, by heat bonding. An image retaining card including a cover heat bonded to an image receptive material having a printed image disposed on its surface exhibits desirable anti-tampering characteristics. In particular, if the protective layer is separated from the image receptive material, the printed image will be substantially distorted and/or destroyed. For example, during delamination, a portion of the ink may adhere to the cover and a portion of the ink may adhere to the image receptive material, making image alteration difficult.